1. Field of the Invention
In certain manufacturing operations, it is necessary to apply pressure evenly along a flat or nearly flat surface. In particular, the problem arises when bonding bars of ferrite material together to form a composite bar from which individual ferrite heads for use in magnetic recording are sawed. In such applications, tolerances are extremely tight, as little as .+-.5 micro-inches in the spacing between the bars which are bonded together, said spacing forming the flux gaps for the cores. These tolerances must be accurately maintained along a relatively long interface, since many cores are sawed from a single bar. Of course, the aforementioned even clamping pressure on the individual bars must be maintained throughout the bonding operation.
The problem is complicated by several factors. Even though many individual cores are sawed from the composite bar, the bar itself is still quite small and difficult to work with. It is made from ferrite, an extremely hard material which is not easy to accurately machine over large areas to true flatness. Thus, minor deviations from true flatness are inevitable along the mating surfaces of the individual bars to be bonded together. An even more serious problem, however, is that the bonding takes place at elevated temperatures, temperatures at which metals normally lose much of their strength and often even melt. Thus, it is imperative that the vise which clamps the individual bars together to permit bonding be unaffected by elevated temperatures so as to permit the bonding to result in accurate widths of the bonding material along the bonding interface. 2. Description of the Prior Art
An ordinary flat or grooved jaw face in such a vise is not satisfactory because of the unavoidable deviations from the flatness in the individual ferrite bars. The usual solution is to have individual jaw face parts which will adjust or deflect responsive to load variations across the face as the vise jaws are tightened. The closest art of which inventors are aware is shown by U.S. Pat. No. 3,561,748, which discloses a vise having jaws comprising fingers forming an acute angle with the jaw face, and which deflect a small amount elastically when the vice is tightened on a work piece. Applicants consider this patent to be the closest art of which they are aware. U.S. Pat. No. 988,820 discloses a clamping structure having porcelain jaws, a refractory material such as forms a part of the invention of this application. The prior art includes many other U.S. Patents whose jaws comprise individually adjustable segments, such as those shown in U.S. Pat. Nos. 1,453,176; 1,519,225; 2,658,415; 2,754,708; 3,592,461; and 3,608,809. Applicants feel that none of these devices alone or in combination are suitable for the purposes served by the instant invention.